Generally, electrostatic coating refers to a coating method in which a paint is efficiently applied to a coating target by use of an electrostatic force by negatively charging paint particles and forming an electrostatic field (lines of electric force) with application of a high voltage between the coating target used as an earth electrode and an electrode of the coating apparatus used as a cathode. Electrostatic coating can produce effects such as improvement in coating efficiency (shortening of a coating period because of improved wrap around of the coating) and improvement in paint application efficiency (reduction in the amount of used paint because of an improved ratio of paint amount applied on a coating target).
Since the coating target by electrostatic coating serves as an electrode, the target needs to have a conductivity. When electrostatic coating is performed on a non-conductive coating target, the following techniques are employed:                providing a conductivity to a material by mixing with a conductive material or a conducting agent.        providing a conductivity to a coating surface by application of a conductive film such as a conductive primer.        providing a temporary low conductivity to a coating surface by an antistatic treatment such as application of a surfactant.        providing a low conductivity to a coating surface by grounding of the coating surface and use of a conductive paint.        